JPH11197909A - Throw-away tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To carry out sure and effective ships disposal in a wide cutting range from cutting of superfinishing in a precise process to general cutting. SOLUTION: In a throw-away tip having cutting edges 14... formed at ridge part of a rake surface 12 which is a top surface of a tip body 11 having a polygonal planar shape, and a nose cutting edge 15 formed in a corner part C of the rake surface 12, at which the adjacent cutting edges 14, 14 cross together, the rake angle of the nose cutting edge 15 is charged between the opposite ends 15A, 15B of the nose cutting edge 15 so that the rake angle of the center 15C thereof is larger or smaller than that of the opposite ends 15A, 15B thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away insert (hereinafter, referred to as a "cut-away insert") capable of exhibiting reliable and effective chip processing performance in a wide range of cutting areas from super-finishing cutting to general-purpose cutting in precision machining. Chip).

[0002]

2. Description of the Related Art FIGS. 13 to 16 show a conventional chip. In the chips shown in these figures, the upper surface of a chip body 1 having a substantially rhombic flat plate shape is a rake face 2 and each side face is a flank face 3... The intersection of these rake face 2 and each flank face 3. Cutting edges 4 are formed at the ridges, that is, at each side ridge of the diamond-shaped rake face 2.
Further, among the corners of the rake face 2, the corners C, C at which the adjacent cutting edges 4, 4 intersect each other at an acute angle, have a convex arc shape continuous so as to smoothly contact these cutting edges 4, 4. Nose cutting edge 5 is formed. Here, in this chip, as shown in FIGS. 14 to 16, the rake face 2 is formed so as to be depressed at a constant inclination toward the inside from the cutting edge 4 and the nose portion cutting edge 5.
As a result, the cutting edge 4 and the nose portion cutting edge 5 are given a positive rake angle θ.

[0003] A cutting blade 4 is provided inside the rake face 2.
The chip breaker 6 is formed so as to protrude from the rake face 2 with a space between the nose portion cutting blades 5 and 5. As shown in FIG. 13, the chip breaker 6 is spaced equidistantly from the cutting edges 4 in the inner portion of the cutting edges 4 in plan view as viewed from the direction facing the rake face 2. While the breaker wall surface 7 is formed so as to present a rhombus slightly smaller than the rake face 2, the corners C and C facing the nose part cutting edges 5 and 5 have these corners C and C formed therein. It is formed so as to extend in the diagonal direction of the connection and to reach a position close to the nose portion cutting blade 5 at its tip. It is to be noted that reference numeral 8 in the drawing denotes the chip body 1.
This is a mounting hole through which a clamp screw or the like for attaching the to a tool such as a cutting tool is inserted.

However, when cutting and feeding are relatively small and only the periphery of the nose portion cutting edge 5 is used, such as finish cutting, in cutting using such a chip, the nose portion cutting edge is used. The chips generated by 5 have a small thickness and a small width.
Immediately after the generation of the chips, the chips collide with the tip of the chip breaker 6 close to the nose portion cutting blade 5, so that the chips can be cut off quickly. On the other hand, cutting and feed are relatively large like rough cutting,
When a portion from the nose portion cutting edge 5 to the cutting edge 4 is used, a thick and wide chip is generated. In the chip having the above-described configuration, such a chip is generated by the cutting edge 4.
While rubbing on the rake face 2 between the chip breaker 6 and the chip breaker 6, the chip receives the resistance and collides with the chip breaker 6 to be bent, curled, and cut. Therefore, according to the above-mentioned chip, efficient chip processing can be achieved in a general-purpose cutting region from rough cutting to normal finish cutting.

[0005]

However, when the depth of cut and feed are set to be smaller than those of the above-mentioned ordinary finishing, for example, in the case of super finishing in precision machining, the chips are thinner and wider. While it is difficult to be cut because it becomes narrow and slightly stretched, the portion of the nose portion cutting edge 5 that is used for cutting and generates chips is also reduced, so that the chip for general-purpose cutting as described above is generated. It is difficult to make sure that the scraps collide with the tip of the chip breaker 6 for processing. Therefore, in the case of such super-finishing cutting, the tip of the chip breaker 6 is formed closer to the nose portion cutting edge 5, and the chips generated by the nose portion cutting edge 5 can be reliably removed from the chip breaker. 6 must be made to collide.

However, if the tip of the chip breaker 6 is too close to the nose cutting edge 5 as described above, when the chip is used for general general-purpose cutting, the thick-walled part having a large thickness, particularly in rough cutting, is used. When chips are generated, the chip breaker 6 can be used before the chips are sufficiently rubbed on the rake face 2.
And the pocket portion defined between the cutting edge 4 and the nose portion cutting edge 5 and the chip breaker 6 becomes small, and as a result, chips tend to be clogged and the processing performance is impaired. May be Further, when the chips tend to be clogged in this way, cutting resistance increases and chattering occurs, which may lead to deterioration of finished surface accuracy and shortening of chip life.

Further, when the tip of the chip breaker 6 is brought closer to the nose cutting edge 5, the concave curved portion P where the breaker wall 7 at the tip of the chip breaker 6 intersects the rake face 2 also has a nose portion. Although it comes close to the cutting edge 5, stress due to the cutting load acting on the nose portion cutting edge 5 tends to concentrate on such a concave portion P. If the tip body 1 is too close, for example, when cutting a hard material, the chip body 1 may be broken from the concave portion P. Moreover, since the risk of this loss increases as the rake angle θ increases, the chip cannot increase the rake angle θ to improve the sharpness of the cutting edge 4 and the nose portion cutting edge 5. As a result, the cutting resistance is further increased. Therefore, conventionally, such a chip for super-finishing cutting cannot be used for general general-purpose cutting, and cutting has to be performed by preparing a dedicated chip for each.

The present invention has been made under such a background, and as described above, in a wide range of cutting range from super-finishing cutting in precision machining to general-purpose cutting, reliable and effective chip processing. It is an object of the present invention to provide a chip capable of achieving the following.

[0009]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and achieve such an object, the present invention provides a chip body having a polygonal flat plate shape, in which the upper surface is a rake face. A cutting edge is formed on the side ridge, and at the corner of the rake face where the adjacent cutting edges intersect,
In a chip having a nose portion cutting edge, a rake angle of the nose portion cutting edge is changed between both ends of the nose portion cutting edge. Therefore, the chips generated by the nose portion cutting edge are generated in a state in which the rake angle of the nose portion cutting edge is changed, and thus the chip is easily divided by receiving a bending moment in the width direction thereof. That is, such chips are bent by receiving resistance in the longitudinal direction when rubbing on the rake face connected to the nose cutting edge, or by colliding with a chip breaker formed on the rake face. However, even thin chips having a narrow width due to super-finishing are easily cut. For this reason, even in the case of the super-finishing cutting in which the cut and the feed are minute, the chip processing can be surely performed without the tip end of the chip breaker being too close to the nose part cutting blade as in the related art.

In changing the rake angle of the nose cutting edge, one of the reasons is that the rake angle of the nose cutting edge is set to be larger at the intermediate portion than at both ends of the nose cutting edge. It can be set to be larger. However,
In the case of adopting such a configuration, a sufficient edge angle can be secured at both end portions of the nose portion cutting edge and the cutting edge portion of the side ridge portion of the rake face connected to the nose portion cutting edge. In general finish cutting or rough cutting to be used, while the cutting edge strength that can withstand a large cutting load can be given to the portion, the rake face connected to the nose cutting edge is
Since it will be formed in a valley shape that depresses from both ends to the middle along the nose cutting edge, in super-finishing cutting, the generated chips are guided to the bottom of this valley and bent, It is possible to surely divide.
In particular, by setting the rake angle of this nose part cutting edge to be the maximum on the bisector of the corner,
When the depth of cut or feed is small as in super-finishing cutting, the tip of the nose cutting edge, that is, the portion located on the bisector is mainly used for cutting, giving this tip a sharp sharpness Excellent finishing accuracy can be obtained.

As another one, contrary to the above case, the rake angle of the nose portion cutting edge may be set to be smaller at the intermediate portion than at both ends of the nose portion cutting edge. In this case, in this case, the rake face connected to the nose portion cutting edge is formed in a mountain shape that protrudes from both ends thereof toward the intermediate portion along the nose portion cutting edge. Therefore,
The chips generated by the nose cutting edge are pressed against the slope of this mountain while rubbing the rake face, and are bent by receiving resistance, so that the chip is more reliably divided as in the above case. Can be achieved. In particular, by setting the rake angle of the nose cutting edge to be the minimum on the bisector of the corner, a sufficient cutting edge can be provided at the tip of the nose cutting edge used in super-finishing cutting. Since strength can be imparted, it is possible to prevent the nose portion cutting edge from being damaged, for example, even when superfinishing a work material made of a hard material.

[0012]

1 to 6 show a first embodiment of the present invention.
1 shows an embodiment of the present invention. In the chip of the present embodiment, the chip body 11 is formed in a substantially rhombic flat plate shape from a hard material such as a cemented carbide, and the upper surface thereof is a rake face 12 and each side face is a flank face 13. A cutting edge 14 is formed at the intersection between the surface 12 and each flank 13.
Are formed, and of the corners of the rake face 12, the corners C, C where the adjacent cutting edges 14, 14 intersect each other at an acute angle so as to smoothly contact the cutting edges 14, 14. And a convex arcuate nose cutting edge 15 is formed. In this embodiment, these cutting blades 1
4 and the nose portion cutting blades 15, 15 are formed so as to be located on one plane perpendicular to the thickness direction of the flat chip body 11. Further, the tip of the present embodiment is inclined so that the flank faces 13... Inward toward the lower surface side of the tip body 11, so that the flank faces the cutting blades 14. The surface 13 is a positive tip with a relief angle given in advance.

A chip breaker 16 protruding from the rake face 12 is provided inside the rake face 12.
4 and the nose part cutting blades 15, 15 are formed with an interval. As shown in FIG. 1, the chip breaker 16 has a large space between the cutting edges 14 in an inner portion of the cutting edges 14 in a plan view viewed from a direction facing the rake face 12, The breaker wall surface 17 is formed so as to present a rhombus one size smaller than the rake face 12, while the corners C, C facing the nose cutting edges 15, 15 connect these corners C, C. It is formed so as to extend diagonally in the form of a ridge, and to reach a position close to the nose portion cutting edge 15 with a small space therebetween. In the present embodiment, the protruding portion of the chip breaker 16 is formed so as to protrude in a semi-circular shape from the rake face 12 in a cross section orthogonal to the diagonal line, and the tip thereof is shown in FIG. As shown in FIG. 4, it is formed to have a substantially 1/4 spherical shape. Further, from the center of the rake face 12 to the lower surface of the chip body 11, a mounting hole 18 through which a clamp screw or the like for mounting the chip body 11 to a cutting tool such as a cutting tool is inserted is provided.

In this embodiment, the rake face 1 is used.
2 is connected to the cutting edge 14.
4 so that the rake angle α is constant over the entire length of the cutting edge 14 and away from the cutting edge 14 toward the inside of the chip body 11 as shown in FIG. It is formed on an inclined surface that gradually sinks at a constant gradient. On the other hand, the rake face 12 of the rake face 12 connected to the nose cutting edges 15, 15 has a rake angle with respect to the nose cutting edges 15 between both ends 15A, 15B of each nose cutting edge 15. The nose portion cutting blade 1 is formed so as to change.
The rake angle of 5 is at both ends 15A, 15 of the nose cutting edge 15.
B, the rake angle α is equal to that of the cutting edge 14, and the intermediate portion between the ends 15A, 15B is separated from the ends 15A, 15B so that the rake angle is larger than the rake angle α. And gradually increased in accordance with In particular, in the present embodiment, the rake angle of the nose portion cutting edge 15 is equal to the bisector L of the corner portion C.
When viewed from the upper position, that is, the direction facing the rake face 12, the nose portion cutting edge 15 intersecting with a bisector L of an intersection angle formed by the cutting edges 14, 14 connected to both ends 15A, 15B of the nose portion cutting edge 15. At the position of the center 15C, the maximum rake angle β is set.

However, in the case of performing rough cutting using the nose portion cutting edge 15 to the cutting edge 14 due to a large cutting and feeding by the chip configured as described above, most of the chip is the cutting edge. 14, a rake face portion 12A connected to the cutting edge 14.
While being rubbed, it is bent by receiving resistance and collides with the breaker wall surface 17 of the chip breaker 16 to be cut.
Also, in general finishing cutting or the like in which the cut or feed is smaller than this and the substantially entire length of the nose portion cutting edge 15 is used, chips are formed at the tip end of the chip breaker 16 extending so as to approach the nose portion cutting edge 15. The part is immediately separated by colliding immediately after generation.

On the other hand, when performing super-finishing cutting or the like in which the depth of cut or feed is smaller than that of such general finishing cutting, as shown in FIG.
5, only a part thereof is used, and extremely thin chips having a small width are generated. However, in the chip having the above-described configuration, the rake angle of the nose portion cutting edge 15 is increased as described above. The cutting edge 15 is formed so as to change between both ends 15A and 15B of the cutting edge 15, so that the nose cutting edge 15
The chip generated by the above-mentioned method receives a bending moment in the width direction at the time of the generation, and is generated in a state in which the chip is likely to be cut in the longitudinal direction, that is, in the outflow direction A of the chip. In FIG. 6, reference numeral W denotes a work material, reference numeral B denotes a feed direction of a cutting tool to which the above-mentioned chip is attached, reference numeral D denotes a cut in the super-finishing cutting, and reference numeral F
Is the feed of the cutting tool per rotation of the workpiece W.

In the chip having the above-described structure, such chips are bent in the longitudinal direction due to resistance while rubbing on the rake face portion 12B, or are located deep inside the rake face portion 12B. By colliding with the tip of the chip breaker 16, even chips having a small thickness and a small width can be easily cut off.
Efficient chip processing can be achieved without the tip of the nose piece 6 being too close to the nose cutting edge 15. Therefore, according to the chip having the above-described configuration, the position of the chip breaker 16 can be the same as that of the conventional general-purpose cutting chip. Even when used for rough cutting where a wide chip is generated, it is possible to prevent chip clogging and maintain good chip disposability, suppress the increase in cutting resistance due to this chip clogging, and reduce chatter. This can prevent deterioration of the finished surface accuracy and shortening of the chip life, and also prevent loss from the concave portion P where the breaker wall 17 and the rake face portion 12B intersect. A more versatile insert that can be used for general-purpose cutting from super-finishing cutting to general finishing cutting and rough cutting can be provided.

In the tip of the present embodiment, when the rake angle of the nose portion cutting edge 15 is changed in this way, the rake angle of the nose portion cutting edge 15 is larger at the intermediate portion than at both ends 15A and 15B. Is to be bigger,
Accordingly, a large bevel angle can be ensured at both ends 15A and 15B of the nose portion cutting edge 15 and the cutting edges 14 and 14 connected thereto, so that general finishing cutting and rough cutting using these portions can be ensured. In cutting, sufficient cutting edge strength capable of withstanding a large cutting load can be obtained. On the other hand, by adopting such a configuration, the rake face portion 12 </ b> B connected to the nose portion cutting edge 15 is formed along the nose portion cutting edge 15 as shown in FIG.
A and 15B are formed in a valley shape which is depressed toward the middle part, so that chips generated at the time of the above-mentioned super-finishing cutting are formed on the valley bottom along the valley formed by the rake face portion 12B. It flows out and bends at the rake face portion 12B that is concave at the bottom of the valley, or is guided by the valley bottom to collide with the tip of the chip breaker 16 located at the back of the rake face portion 12B. Thereby, it is possible to achieve more reliable division.

Further, in the present embodiment, the rake angle of the nose portion cutting edge 15 is the maximum rake angle β on the bisector L of the corner portion C of the rake face 12 on which the nose portion cutting edge 15 is formed. That is, it is set so that the rake angle β becomes the maximum at the center 15C of the nose portion cutting edge 15. However, in the nose portion cutting edge 15 having a convex arc shape as in the present embodiment, the periphery of the center 15C is the tip end portion. Therefore, in the super finishing cutting or the like, the center 15C of the nose portion cutting edge 15 is used.
Since the periphery of C is used, according to the present embodiment, it is possible to impart sharp sharpness particularly to the nose portion cutting edge 15 around the center 15C used for this super-finishing cutting, and a more excellent finished surface The rake face portion 1 connected to the nose portion cutting edge 15 can be obtained with high accuracy.
The bottom of the valley formed by 2B is located at the center 1 of the nose cutting edge 15.
Since it is formed so as to extend from 5C along the bisector L, the chip generated at the center 15C can be guided more reliably along the valley bottom and can be divided quickly. can get.

Next, FIGS. 7 to 11 show a second embodiment of the present invention.
In this embodiment, the same reference numerals are given to the same parts as those in the first embodiment, and the description will be omitted.
In the present embodiment, when changing the rake angle of the nose portion cutting edge 15 between its both ends 15A and 15B,
The rake angle of the nose portion cutting edge 15 is
At both ends 15A, 15B, the rake angle α is equal to that of the cutting edge 14, and both ends 15A, 15B
In the middle portion between the two, the rake angle is gradually reduced as the distance from both ends 15A, 15B becomes smaller than the rake angle α. In particular, in the present embodiment, the rake angle of the nose portion cutting edge 15 is determined from the position on the bisector L of the corner portion C, that is, from the direction facing the rake face 12.
The center 1 of the nose portion cutting edge 15 intersecting with the bisector L of the intersection angle formed by the cutting edges 14, 14 connected to both ends 15A, 15B
At the position of 5C, it is set so as to form the minimum rake angle γ.

However, even in the chip having such a configuration, both ends 15A, 15B of the nose portion cutting blade 15 are provided.
Since the rake angle changes between the two, the chips generated by the nose portion cutting edge 15 are generated in a state in which the chips are likely to be cut by receiving a bending moment in the width direction, and therefore, are thin and thin. Even in super-finishing cutting in which chips with a small width are generated, the chip breaker 16 can be surely processed without causing the nose portion cutting edge 15 to be too close to each other. A highly versatile chip that can be used can be provided. Further, in the present embodiment, the fan-shaped rake face portion 12C connected to the nose portion cutting edge 15 is formed in a mountain shape protruding from both ends 15A and 15B along the nose portion cutting edge 15 toward the middle portion. And the chips generated by the nose part cutting edge 15
While rubbing C, it is bent by receiving resistance by being pressed against the slope of the mountain, and as a result, chips can be more reliably separated as in the first embodiment.

Further, in the present embodiment, the rake angle of the nose portion cutting edge 15 is on the bisector L of the corner portion C, that is, the nose portion cutting edge 15 serving as a tip portion used in super-finishing cutting. Is set to be the minimum rake angle γ at the center 15C of
Since a sufficient edge strength can be given also to the center 15C of the nose portion cutting edge 15, the nose portion cutting edge 15 may be damaged, for example, even when performing super-finishing cutting of a work material made of a hard material. Can be prevented. Further, since the nose portion cutting edge 15 has the minimum rake angle γ on the bisector L of the corner portion C in this manner, the rake face portion 12C continuous with the nose portion cutting edge 15 is formed.
Is formed in a mountain shape having a ridgeline on the bisector L as shown in FIG. 11, and chips generated by the periphery of the center 15C of the nose portion cutting edge 15 during superfinishing cutting are: The rake face portion 12C along the ridgeline of this mountain
While being rubbed on the top, it is bent by receiving resistance, or is pressed against the slope of the mountain formed by the rake face portion 12C even if it comes off the ridgeline, and is bent by receiving resistance to be surely divided.

In the first and second embodiments, both ends 15A, 15B of the nose portion cutting edge 15 are provided.
The rake face portions 12B, 12C whose rake angles with respect to the nose portion cutting edge 15 change between them are formed so as to be directly connected, but a land is formed on the nose portion cutting edge 15 side of the rake face portions 12B, 12C. The land may be a negative land or a positive land. Further, the chips of the first and second embodiments are both positive chips, but may be negative chips. Further, in the first and second embodiments, the rake angle α of the cutting edge 14 and the rake angles α, β, γ of the nose portion cutting edge 15 are all set on the regular angle side. In the embodiment, as long as α <β is satisfied,
Further, in the second embodiment, these may be set to the negative angle side as long as α> γ is satisfied, and the rake angle of the nose portion cutting edge 15 changes between the positive angle and the negative angle. May be set.

Furthermore, in the tip of each of the above embodiments, the cutting edge 14 and the nose cutting edge 15 are formed by the tip main body 1.
1 are formed on one plane perpendicular to the thickness direction of the chip body 11 so as to form a straight line in a side view of the chip body 11 which is a flank 13.
The tip 4 and the nose cutting edge 15 may be curved in the thickness direction of the tip body 11 so as to form a curved shape in the side view. Further, regarding the cutting blade 14, the tip body 11
The nose portion cutting edge 15 may be formed in a so-called chamfered corner, which is linear in the plan view. Good.

Further, in the above-described first and second embodiments, the rake angle of the nose portion cutting edge 15 is set at the opposite ends 15.
The middle portion between both ends 15A and 15B is larger or smaller than A and 15B, and especially the center 15C of the nose portion cutting edge 15 located on the bisector L of the corner C.
Is set to be the maximum or minimum. For example, it is set to be maximum or minimum at a position deviated from the center 15C to one of both ends 15A and 15B, or from one of both ends 15A and 15B. The rake angle may gradually increase or decrease toward the other side. This is particularly effective in the case of a so-called self-tapping tip in which the directions of the cutting blade 14 and the nose part cutting blade 15 used for cutting are limited to a specific direction in advance. The rake angle of the nose cutting edge 15 gradually increases or decreases between its both ends 15A and 15B, and then gradually decreases or increases at the center 15C, but increases between both ends 15A and 15B. And the reduction may be repeated.

[0026]

Next, the effects of the present invention will be specifically described with reference to examples of the present invention. In this example, the chip of the first embodiment shown in FIGS.
Cutting was performed using the insert of the second embodiment shown in FIGS. 7 to 11 while changing the cut and feed, and the processing performance of chips at that time was investigated. In addition, as a comparative example, cutting was performed under the same cutting conditions using the chips of the conventional example shown in FIGS. 13 to 16, and the processing performance of the chips at that time was compared.

However, the work material at this time was S45C, and the cutting speed was 200 m / min. Also, the chips used were all the same size made of cemented carbide,
The nose radius of the nose part cutting edges 5, 15 is 0.4 mm, and the chip breakers 6-1 from the center (tip) of the nose part cutting edges 5, 15
6 is 1.3 mm, the distance between the cutting edges 4 and 14 and the breaker wall surfaces 7 and 17 of the chip breakers 6 and 16 is 1.1 mm, and the intersection of the cutting edges 4 and 14 intersect at the corner C. The angle was 80 °, and the clearance angles of the flank surfaces 3 and 13 were 7 °. Further, the rake angle θ of the chip of the comparative example based on the conventional example is 8 °, while the rake angle α of the chip of the example based on the first embodiment is 8 ° and the rake angle β is 1 °.
The rake angle α of the chip of the example according to the second embodiment was 8 °, and the rake angle γ was 0 °.

As a result, in the inserts of the examples based on the above-described first and second embodiments, in any case, the cutting depths which are almost equal from the ordinary rough cutting and the finishing cutting to the super finishing cutting where the cutting and the feed are extremely small. In the insert of the comparative example, the same chip processing as the insert of the example was achieved in the rough cutting with a large depth of cut and feed and the normal finish cutting, while excellent chip processing performance was obtained in the range of feed and feed. However, when the cutting and feeding were extremely small, the chips flowed out without being divided, resulting in the cutting tools being entangled and hindering the cutting. The results are shown in FIG. 12 as the range of the cut and the feed in which the chips can be reliably processed.
, And the chip of the comparative example is denoted by reference numeral N.

[0029]

As described above, according to the present invention,
The rake angle of the nose part cutting edge formed at the corner of the rake face is changed between these ends by making the middle part larger or smaller than the both ends of the nose part cutting blade. Therefore, the chips generated by the nose portion cutting edge are generated in a state where they are likely to be cut by receiving a bending moment in the width direction at the time of the generation. Then, such chips are bent by receiving resistance while rubbing on the rake face connected to the nose part cutting edge, or by colliding with a chip breaker or the like,
Since such chips can be reliably separated, even chips generated by ultra-finish cutting with extremely small depth of cut and feed can be processed smoothly without bringing the chip breaker too close to the nose cutting edge. Becomes

[Brief description of the drawings]

FIG. 1 is a plan view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX in FIG.

FIG. 3 is a sectional view taken along line YY in FIG.

FIG. 4 is a sectional view taken along the line ZZ in FIG. 1;

FIG. 5 shows a corner C of the rake face 12 of the embodiment shown in FIG.
It is a perspective view which shows the periphery.

FIG. 6 is a plan view showing a case where super-finishing cutting is performed according to the embodiment shown in FIG. 1;

FIG. 7 is a plan view showing a second embodiment of the present invention.

8 is a sectional view taken along the line XX in FIG.

FIG. 9 is a sectional view taken along line YY in FIG. 7;

FIG. 10 is a sectional view taken along the line ZZ in FIG. 7;

11 is a perspective view showing the vicinity of a corner C of the rake face 12 of the embodiment shown in FIG. 7;

FIG. 12 is a view schematically showing chip processing performance when cutting is performed by an example according to the present invention and a comparative example according to a conventional example.

FIG. 13 is a plan view showing a conventional throw-away tip.

14 is a sectional view taken along the line XX in FIG.

FIG. 15 is a sectional view taken along the line YY in FIG.

16 is a sectional view taken along the line ZZ in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Tip main body 12 Rake surface 12A Rake surface part connected to cutting blade 14 12B Rake surface part connected to nose part cutting blade 15 13 Relief surface 14 Cutting blade 15 Nose part cutting blade 15A, 15B Both ends of nose part cutting blade 15 15C Nose part Center of cutting edge 16 Chip breaker 17 Breaker wall C Corner of rake face 12 L Bisector of corner C α Rake angle at both ends 15A, 15B of nose cutting edge 15 β, γ Center of nose cutting edge 15 Rake angle at 15C

Claims (5)

[Claims] An upper surface of a chip body having a shape of a polygonal flat plate is a rake face, a cutting edge is formed at a side edge of the rake face, and the rake face at which the adjacent cutting edges intersect with each other. A corner having a nose cutting edge, wherein the rake angle of the nose cutting edge varies between both ends of the nose cutting edge. Away tip. 2. The throwaway according to claim 1, wherein the rake angle of the nose portion cutting edge is set to be larger at an intermediate portion than at both ends of the nose portion cutting edge. Chips. 3. The indexable insert according to claim 2, wherein the rake angle of the nose cutting edge is maximum on a bisector of the corner. 4. The throwaway according to claim 1, wherein the rake angle of the nose portion cutting edge is set to be smaller at an intermediate portion than at both ends of the nose portion cutting edge. Chips. 5. The indexable insert according to claim 4, wherein the rake angle of the nose cutting edge is minimum on a bisector of the corner.